Press for operating on metal sheets



H. A. AND R. H. GRIFFITHS. PRESS FOR OPERATING 0N METAL SHEETS.

APPLICATION FILED AUG.23. 1921.

1,415,838. Patented M 1922.

2 SHEET EET 1.

JJCA. 611 Lzffzktlw H. A. AND R. H. GRIFFITHS.

PRESS FOR-OPERATING 0N METAL SHEETS. APPLIcIITIoII FILED AUG.23. I92I.

1,415,838, Patented May 9, 1922.

2 SHEETS-SHE UNITED STATES:

PATENT OFFICE.

orsurrou COLDFIELD, ,nNeLaNn.

Panes roe OPERATING on METAL snnnrrs.

Specification of Letters Patent.

Patented Ma 9, 1922.

Application flled August 23, 1921; Serial No. 494,534.

To all whom it may ounce m:

@Beit known that we, HARRY ALBERT GRIF- rI'rrIs, residing at 8 Chad Road, Edgbaston,

in the cit or Birmingham, England, and RICHARD lLxNsoN Gmrrrriis, residing at Coldfield, in the county of arwick, England, StlbjGCtSfJiii the King of Great Britain and "Ireland, have invented certain new and useful:Improvements Re-- lating t0 Presses for Operating on Metal Sheets, forwhich I filed an application for patentin Great Britain 23970, dated Aug.

.17, 1920, and of which the following is a specification.

Thisinvention relates to drawing and like presses for operating on metal sheets, as e. g in themanufacture of metal boxes from circular sheet metal blanks. It is usual to arrange with the lower tools a plurality of stopsagainst which the blanks are fed, and by which the blanks are properly positioned relativelyto the tools. The stops necessarily project above the lower tools and ordinarily are fixed, and as a consequence it lSllSl'ltLllj,

necessary to adapt the upper or movable tools (e. g. by the provision oi. apertures or channels therein) to clear the stops when they come into actionon the lower tools. Thisconditionis undesirable inasmuch as the shaping of thetoolsto accommodate or clear the stops often resultsin weakening of the tools, and further additional labour is involved in the production of the tools.

The object of the present invention is to avoid the disadvantages of the ordinary stops, and for this purpose the invention comprises the use of hinged stopswhich automatically takeup the operative position relatively to the lower tools and which recede to an inoperative position under the action of the upper or movable tools.

In the three accompanying sheets of on planatory drawings Figures 1 and 2 are sectional side elevation and plan illustrating one application of the invention to press tools for operating on circular blanks.

Figure 3 is aside view illustrating a modified device.

shown in Figures 1; and 2, a pair of brackets Figures 4 and 5 are respectively similar a are secured in convenient positions on the bed 'ofthe machine adjacent to the lower tools, which in the example illustrated comprise a central fixed portion 6, .an outer ring 0, the latter being supported by parts d on a spring Oneach bracket is pivoted a segmental or lever like stop 7 which under the action of a spring gtakesup aneffective position relatively to the tools. The edge adpicent to the lower tools is arc-shaped in orc er thatit may remain operative throughout a suitable range of angular movement. The blanks as h are fed up to the stops singly in the usual way along a lineindicated by the arrow F igure 2. When the upper or movable tool 2' approaches the lower tools it first engages the stops, and during the remainder of its movement causes the stops to swing about their pivots against the action of the springs, the oper ative edges of thestops remainingin contact with the blanks throughout this movement. After the shaping operation on the blank, thestops return with the upper tool to the operative position under the action of the springs. l

By this invention we are able to avoid in a simple and efiective manner the disadvantages above mentioned of the ordinary fixed stops without in any way interfering with the proper positioning of the blanks. If desired the operative edges f of the stops may be made slightly eccentric or cam shaped as shown in Fig. 1, so that during their movement they impart a slight sliding movement of the blanks for the purpose of accurately centering the latter relatively to the tools.

In some cases it is advantageous to hold the stops in the depressed. position, until the upper tool has returned almost to its initial position, particularly where difiiculty might otherwise be found in getting the blanlr after the shaping operation clear of the stops during the return of the upper tool. We then arrange in conjunction with one or all of. the hinged stops as shown in Figure 3 a catch lever j which under its own weight or a spring rests on a support la. During the descent of the upper tool a projection Z on the hinged stop is caused to engage a notch m on the catch lever; the stop lever is then held until released. In conjunction with the part of the machine carrying the upper tool is arranged a trip member n I upper which when the said tool approaches the limit of its movement tilts the catch lever and releases the stop. Meanwhile the shaped blank has had time to move clear of thetools. The catch lever may be actuated for releasing the stop lever in any other convenient manner.

For dealing with rectangular blanks we shape the hinged stops as shown in Figures 4L and 5. These are arranged at a pair of opposite sides of the lower tools and are adapted to abut against the blank at its front and rear ends. The front end of each stop is splayed out to avoid obstructing the free movement of the blank while it is being inserted in position on the lower tools, and the rearend of each stop is formed with a projeet-ion f which limits the forward movement of the blank. In other particulars-the mechanism-is essentially the same as that above described. It will be understood that each hinged stop may be catch lever as shown in quired.

Having thus described our invention what we claim as new and desire to secure by Letters Patent is:-

1. In presses for operating on metal sheets or blanks, the combination with a fixed tool, ofa stop pivotally mounted alongside of the saidtool and having a stop portion extending into close proximity to the edge of said tool, means forautomatieally moving the stop to'a position where the stop portion projects beyond the operative surface of said tool, and a second tool movable toward and away from the fixed tool and engageable with said stopportion for gradually mov- Figure 3 if re- ,ing the latter over the edge of the fixed tool when the movable tool is moving toward said fixed tool.

2. A. combinationas claimed in claim 1 in which the'stop portion is provided with a curved surface adapted to move across the edge of said fixed tool.

A. combination of the kind defined by claim 1 in which the stop portion is provided with an arc-shaped operative surface adaptprovided with a.

ed to move across the edge of said fixed tool, the are of said surface being struck from a center arranged eccentrically to the pivot of said stop.

4. A combination of the kind claimed in claim 1 including latching means adapted to engage said stop for locking the same in depressed position while the movable tool is moving toward the fixed tool, and means movable with the movable tool for releasing said latching means after the movable tool has moved away from the fixed tool.

5. In presses for operating on metal sheets or blanks, the combination with a fixed tool, a slidable member surrounding said tool and having its upper surface normally in alignment with the upper surface of the tool, means for urging the sliding member into a position where its upper surface is in the same plane as the upper surface in the fixed tool, standards arranged at the sides of said tool, substantially horizontal arms pivotally mounted on said standards andprovided at their outer ends with curved operative surfaces arranged a jacent to the upperedge of said sliding member, means for normally holding the outer ends of said arms in a position where they project above the upper surface of the fixed tool, and a tool movable'toward and away from said fixed tool and engageable with the outer ends of said arms for causing the curved surfaces of the same to move across the upper edge of said sliding member when the movable tool descends.

6. A combination of the kind defined by claim 5 including latching means for automatically locking the outer ends of said arms in depressed position after they have been forced to this position by the movable tool, and means movable with the movable tool for releasing said latching means at a time when the movable tool has nearly com pleted its ascending movement.

In testimony whereof we have signed our names to this specification.

HARRY ALBERT GRIFFITHS. RICHARD HANSON GRIFFITHS. 

